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Guava (Psidium guajava)A Garden or Orchard Tree with Invasive Potential
Guava fruit are valued for their high Vitamin C content and aromatic flavour, but in the wrong location, the trees can invade environments with high biodiversity values.
Native to tropical America, the Guava is a popular fruit tree grown throughout tropical and subtropical parts of the world. With seeds readily carried by birds and bats that also enjoy the fruit, it has become a major environmental weed in parts of South Africa, Australia and Pacific Islands including Hawaii and the Galápagos Islands. Taxonomy and DescriptionA member of the family Myrtaceae, the Guava is also known as the Common Guava or Yellow Guava. The Royal Botanic Gardens, Sydney’s Plantnet website describes the Guava as a shrub or tree growing up to 6 m high. Leaves are opposite on the stem, elliptic to oblong with a tapered point. Flowers are white and the fruit is a round to pear-shaped yellow berry with persistent calyx lobes. Inside, numerous hard-coated seeds are embedded in succulent pink flesh. There are numerous cultivars, with fruit size and colour variable. Growing and Using the GuavaThe Guava is a hardy plant growing in a wide range of conditions, preferring warm moist climates but tolerant of dry soils and light frost. It is an important commercial crop in many countries, and is used for nutritious juices, jams, eaten fresh or lightly stewed. Medicinal uses have been attributed to the leaves (antimicrobial properties and for the treatment of diarrhoea). Ecological ImpactsThe Guava can overrun open ground forming monocultural stands, competing for resources with native plants that might otherwise colonise cleared areas. On the Galápagos Islands, hillslopes of moss and lichen-encrusted Guava trees with dense understorey of introduced Rubus species effectively block any regeneration of native species. Controlling Guava InfestationsGuava trees are difficult to kill. Cut stumps regrow to form multi-stemmed trees. Treatment with low-toxicity herbicides is often unsuccessful as new sprouts from the base of apparently dead trunks and stumps can appear several years after treatment. Expert advice is essential. Avoiding Weed ProblemsAuthorities in some districts where environmental weeds are problematic will list and recommend avoidance of some garden species. It may be illegal to grow them. Check locally, and if the Guava is, or potentially could be, an environmental weed in your area, consider responsible options. The Guava can be a disappointing garden or orchard plant. In Australia, untreated fruits succumb to fruit-fly infestation, and birds enthusiastically steal the fruit. It may be preferable to plant an alternative fruit species that does not have invasive potential. If only a Guava will do, net the fruiting trees to avoid removal and seed dispersal by birds and frequently remove and destroy fallen fruit.
The copyright of the article Guava (Psidium guajava) in Plant Species is owned by Barbara Stewart. Permission to republish Guava (Psidium guajava) in print or online must be granted by the author in writing.
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